中文摘要：

随着我国城市化进程的加快和隧道工程逐步向深部开发的必然趋势,上软下硬地层隧道工程将会越来越普遍。围岩分级是上软下硬地层隧道工程勘察、设计、施工的基本依据,也是保障工程施工安全、运营安全的基础,其对隧道工程来说是基础性的工作也是关键性的工作。在概括了解围岩分级概念的基础上,从国内外围岩分级的发展史出发描述了当前上软下硬地层隧道围岩分级的研究现状,针对性地阐述了目前在我国常用的三种围岩分级方法：Q系统、RMR分类方法以及公路隧道围岩分级BQ法。指出围岩分级研究中存在的一些问题,发现在目前的研究中还没有建立专门的上软下硬复合地层隧道围岩分级方面的研究体系,最后指出未来我国隧道围岩分级的发展趋向。

英文摘要：

As China＇s urbanization process speeding up and the tunnel engineering gradually to deep development inevitable trend,upper soft and lower hard stratum tunnel engineering will be more and more common. Classification of surrounding rock is not only the basic basis of engineering investigation,design,construction in upper soft and lower hard stratum tunnel,but also the basic of ensuring the safety of engineering construction and operation,it is not only the basic work but also the key work for the tunnel engineering. On the basis of a comprehensive understanding of the concept of classification of surrounding rock,in order to achieve the purpose of describing the research status of classification method of surrounding rock of upper soft and lower hard stratum tunnel at present from the history of the development of domestic and international classification of surrounding rock,by means of narrating three foreign methods of classification of surrounding rock at present commonly used in domestic： Q system and RMR classification,as well as the method of surrounding rock classification of surrounding rock in the field of highway,namely the surrounding rock classification of highway tunnel BQ. It not only points Some of the problems existing in the study of classification of surrounding rock that special system of research on classification method of surrounding rock of upper soft and lower hard stratum tunnel has not been established in the current study,but also points out the development trend of surrounding rock classification in the future,in the end.